Flora raised her hand to her throat, gave a little cry, and I hurried to catch her as she fell. She had fainted, and Blunt and I carried her upstairs and laid her on her bed. Then I got him to wake Mrs Ackroyd and tell her the news. Flora soon revived, and I brought her mother to her, telling her what to do for the girl. Then I hurried downstairs again.

I met the inspector just coming from the door which led into the kitchen quarters.

'How's the young lady, doctor?' 'Coming round nicely. Her mother's with her.' 'That's good. I've been questioning the servants. They all declare that no one has been to the back door tonight. Your description of that stranger was rather vague. Can't you give us something more definite to go upon?' 'I'm afraid not,' I said regretfully. 'It was a dark night, you. see, and the fellow had his coat collar well pulled up and his hat squashed down over his eyes.' 'H'm,' said the inspector. 'Looked as though he wanted to conceal his face. Sure it was no one you know?' I replied in the negative, but not as decidedly as I might have done. I remembered my impression that the stranger's voice was not unfamiliar to me. I explained this rather haltingly to the inspector.

'It was a rough, uneducated voice, you say?' I agreed, but it occurred to me that the roughness had been of an almost exaggerated quality. If, as the inspector thought, the man had wished to hide his face, he might equally well have tried to disguise his voice.

'Do you mind coming into the study with me again, doctor? There are one or two things I want to ask you.' I acquiesced. Inspector Davis unlocked the door of the lobby, we passed through, and he locked the door again behind him.

'We don't want to be disturbed,' he said grimly. 'And we don't want any eavesdropping either. What's all this about blackmail?' 'Blackmail!' I exclaimed, very much startled.

'Is it an effort of Parker's imagination? Or is there something in it?' 'If Parker heard anything about blackmail,' I said slowly, 'he must have been listening outside this door with his ear glued against the keyhole.' Davis nodded.

'Nothing more likely. You see, I've been instituting a few inquiries as to what Parker has been doing with himself this evening. To tell the truth, I didn't like his manner. The man knows something. When I began to question him, he got the wind up, and plumped out some garbled story of blackmail.' I took an instant decision.

'I'm rather glad you've brought the matter up,' I said. 'I've been trying to decide whether to make a clean breast of things or not. I'd already practically decided to tell you everything, but I was going to wait for a favourable opportunity. You might as well have it now.' And then and there I narrated the whole events of the evening as I have set them down here. The inspector listened keenly, occasionally interjecting a question.

'Most extraordinary story I ever heard,' he said, when I had finished. 'And you say that letter has completely disappeared?

It looks bad - it looks very bad indeed. It gives us what we've been looking for - a motive for the murder.' I nodded.

'I realize that.' 'You say that Mr Ackroyd hinted at a suspicion he had that some member of his household was involved? Household's rather an elastic term.' 'You don't think that Parker himself might be the man we're after?' I suggested.

'It looks very like it. He was obviously listening at the door when you came out. Then Miss Ackroyd came across him later bent on entering the study. Say he tried again when she was safely out of the way. He stabbed Ackroyd, locked the door on the inside, opened the window, and got out that way, and went round to a side door which he had previously left open. How's that?' 'I want to see if Mr Raymond can tell us anything about this dagger,' he explained.

Locking the outer door behind us again, we made our way to the billiard room, where we found Geoffrey Raymond. The inspector held up his exhibit.

'Ever seen this before, Mr Raymond?' 'Why - I believe - I'm almost sure that is a curio given to Mr Ackroyd by Major Blunt. It comes from Morocco - no, Tunis. So the crime was committed with that? What an extraordinary thing. It seems almost impossible, and yet there could hardly be two daggers the same. May I fetch Major Blunt?' Without waiting for an answer, he hurried off.

'Nice young fellow that,' said the inspector. 'Something honest and ingenuous about him.' I agreed. In the two years that Geoffrey Raymond has been secretary to Ackroyd, I have never seen him ruffled or out of temper. And he has been, I know, a most efficient secretary.

In a minute or two Raymond returned, accompanied by Blunt.

'I was right,' said Raymond excitedly. 'It is the Tunisian dagger.' 'Major Blunt hasn't looked at it yet,' objected the inspector.

'Saw it the moment I came into the study,' said the quiet man.

'You recognized it, then?' Blunt nodded.

'You said nothing about it,' said the inspector suspiciously.

'Wrong moment,' said Blunt. 'Lot of harm done by blurting out things at the wrong time.' He returned the inspector's stare placidly enough.

The latter grunted at last and turned away. He brought the dagger over to Blunt.

'You're quite sure about it, sir. You identify it positively?'

'Absolutely. No doubt whatever.' 'Where was this - er - curio usually kept? Can you tell me that, sir?' It was the secretary who answered.

'In the silver table in the drawing-room.' 'What?' I exclaimed.

The others looked at me.

'Yes, doctor?' said the inspector encouragingly.

'It's nothing,' said the inspector again, still encouragingly.

'It's so trivial,' I explained apologetically. 'Only that when I arrived last night for dinner I heard the lid of the silver table being shut down in the drawing-room.' I saw profound scepticism and a trace of suspicion on the inspector's countenance.

'How did you know it was the silver table lid?' I was forced to explain in detail - a long, tedious explanation which I would infinitely rather not have had to make.

The inspector heard me to the end.

'Was the dagger in its place when you were looking over the contents?' he asked.

'I don't know,' I said. 'I can't say I remember noticing it - but, of course, it may have been there all the time.' 'We'd better get hold of the housekeeper,' remarked the inspector, and pulled the bell.

A few minutes later Miss Russell, summoned by Parker, entered the room.

'I don't think I went near the silver table,' she said, when the inspector had posed his question. 'I was looking to see that all the flowers were fresh. Oh! yes, I remember now.

The silver table was open - which it had no business to be, and I shut the lid down as I passed.' She looked at him aggressively.

'I see,' said the inspector. 'Can you tell me if this dagger was in its place then?' Miss Russell looked at the weapon composedly.

'I can't say I'm sure,' she replied. 'I didn't stop to look. I knew the family would be down any minute, and I wanted to get away.' 'Thank you,' said the inspector.

There was just a trace of hesitation in his manner, as though he would have liked to question her further, but Miss Russell clearly accepted the words as a dismissal, and glided from the room.

'Rather a Tartar, I should fancy, eh?' said the inspector, looking after her. 'Let me see. This silver table is in front of one of the windows, I think you said, doctor?' Raymond answered for me.

'Yes, the left-hand window.' 'And the window was open?' 'They were both ajar.' 'Well, I don't think we need go into the question much further. Somebody - I'll just say somebody - could get that dagger any time he liked, and exactly when he got it doesn't matter in the least. I'll be coming up in the morning with the chief constable, Mr Raymond. Until then, I'll keep the key of that door. I want Colonel Melrose to see everything exactly as it is. I happen to know that he's dining out the other side of the county, and, I believe, staying the night…' We watched the inspector take up the jar.